There are a number of different ways to react when you don’t understand or didn’t hear what someone said in Portuguese. Let’s take a look:

1. Oi?

This is frequently used when you didn’t catch what the person said. Though it literally means hi, it is also used as what?

2. Como?

Though this also means how, it is a more formal way to say what? when you didn’t hear someone.

3. O que? / Que?

These mean what? and imply you didn’t understand or hear the person.

4. O que que é?

This is a slangier version of #3, which rougly translates to “What was that?”

5. Como é que e?

This is similar to #5, which also means “What was that?” or “I didn’t catch that.”

6. Como você disse?

This is a more formal way of reacting, which means, “What did you say?” or “Come again?”